FDA Re-Approves Formerly Withdrawn Opioid Shown Effective Against OA Pain

October 20, 2014
Lois Wingerson

Pfizer expects to release Embeda (morphine sulfate and naltrexone hydrochloride), approved in 2009 based on osteoarthritis studies but withdrawn by another firm in 2011 due to concerns over abuse, sometime early next year.

The US Food and Drug Administration (FDA) today approved new labeling to allow the reintroduction of an opioid drug intended for daily use by patients with chronic pain unrelieved by other treatments. According to Pfizer the anti-abuse drug Embeda, which contains extended-release morphine sulfate and sequestered naltrexone hydrochloride, an opioid antagonist, should be available early next year.

It is the first and only approved form of morphine designed to deter abuse, answering longstanding demands from pain specialists and others interested in chronic pain.

Embeda was approved in 2009, based on a randomized trial including 547 osteoarthritis (OA) patients. The study found the drug significantly (p<0.05) more effective than placebo against moderate-to-severe OA pain according to several standard scales, without causing withdrawal symptoms when taken as directed. Initially marketed by King Pharmaceuticals, it was withdrawn in 2011, due in part to continued concerns over abuse potential.

The FDA says that, although Embeda is designed not to produce euphoria when ingested nasally or intravenously, it is still not certain that the drug cannot be abused by these routes. The matter will be addressed in postmarketing studies.

Pfizer has announced that it will discontinue its other abuse-deterrent opioid, Avinza (morphine sulfate), and that it has other abuse-deterrent opioids in development.

“More than one-third of extended-release opioids prescribed are morphine, and EMBEDA is the first extended-release morphine with the potential to reduce abuse via the oral and intranasal routes when crushed,” said Steven Romano MD, senior vice president and head of Pfizer's Medicines Development Group, in a press release. “Pfizer believes that abuse-deterrent products, like EMBEDA, are important to help address the growing public health problem of opioid abuse in the US.”